JPH02208116A - Torsion bar type suspension device - Google Patents

Abstract

PURPOSE:To reduce the change in the posture of a vehicle according to its operating conditions for improved driving stability by controlling a liquid- operated expandable mechanism provided between an arm and a vehicle as necessary to carry out vehicle height control and spring constant control at the same time. CONSTITUTION:The liquid pressure of an expandable mechanism 54 provided between an arm 28 and a vehicle by a liquid feed/discharge device is adjusted as necessary and a torsion bar 18 is energized through the arm 28 to adjust the height of a vehicle. At the time of vehicle height adjustment, the middle portion in the torsion bar 18 has a regulated displacement by the reaction force of an accumulator 72 communicated with the expandable mechanism 54 in addition to the reaction force from the vehicle side at one end in the torsion bar 18, so that the spring constant by the torsion bar 18 increases substantially. The spring constant by the torsion bar 18 increases substantially by closing or throttling a control valve 69 regardless of vehicle height adjustment. It is thus possible to reduce the posture change in the vehicle according to its operating conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle suspension, and particularly to a torsion bar type suspension device capable of adjusting vehicle height.

[Conventional technology]

Conventionally, in a torsion bar type suspension device equipped with a torsion bar that is unrotatably supported at one end by a suspension arm and at the other end by a vehicle body, for example,
As shown in Publication No. 1-75006, in a torsion bar type suspension, vehicle height can be adjusted by displacing an anchor arm that is unrotatably attached to the end of the torsion bar on the vehicle body side using a telescoping mechanism. A torsion bar type suspension device is known.

[Problem to be solved by the invention]

However, in the conventional suspension device described above, although it is possible to adjust the vehicle height, it is not possible to control the spring constant of the torsion bar.

For this reason, for example, when the vehicle height is raised to avoid interference between the vehicle body and protrusions caused by ruts on the road surface, the center of gravity of the vehicle is raised, causing the problem of increased roll or pitching of the vehicle body. There is.

Also, for example, when lowering the vehicle height while driving at high speed,
In terms of running stability, it is desirable to increase the spring constant.

[Means to solve the problem]

The present invention was devised in view of the above, and provides a suspension equipped with a torsion bar that is unrotatably supported at one end by a suspension arm and at the other end by a vehicle body. an arm that is unrotatable, a hydraulic expansion and contraction mechanism interposed between the arm and the vehicle body, an Akicomulator that communicates with the hydraulic chamber of the expansion and contraction mechanism, and This is a torsion bar suspension device characterized by comprising: a liquid supply/discharge device for controlling supply/discharge of liquid; and a control valve for controlling mutual communication between the hydraulic chamber and the accumulator.

[Effect]

According to the present invention, the fluid pressure in the hydraulic pressure chamber of the telescoping mechanism is appropriately adjusted by the fluid supply/discharge device, and the torsion bar is biased by the telescoping mechanism to adjust the vehicle height via the arm. By this, the vehicle height can be adjusted, and when the vehicle height is adjusted, in addition to the reaction force from the vehicle body side at the one end of the torsion bar, the intermediate portion of the torsion bar is connected to the telescopic mechanism. Since its displacement is regulated by the reaction force of the accumulator, the spring constant of the torsion bar is substantially increased when viewed from the suspension arm.

Furthermore, regardless of whether the vehicle height is adjusted or not, by closing or restricting the control valve, displacement of the intermediate portion of the torsion bar is completely or almost prevented, so that the suspension The spring constant due to the torsion bar as seen from the arm will be substantially increased.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 1 to 9.

In FIG. 1, reference numeral 2 generally indicates the front suspension according to the present embodiment, 4 and 6 are an upper arm and a lower arm that are swingably supported by a vehicle body frame (not shown), and 8 has an upper end and a lower end that are connected to a ball, respectively. join)
The upper arm 4, lower arm 6, and knuckle 8 constitute a so-called double wishbone type suspension.

14 is a torsion bar composed of a first torsion bar 16 and a second torsion bar 18. As is particularly clear in FIG. 2, the first torsion bar 16 has a spline 16a formed at its front end, and a spline 16a formed on the inner periphery fixed to the lower arm 6 by a bolt 20.
It is unrotatably fitted into an anchor 22 having a diameter 2a.

In FIG. 2, reference numeral 24 designates a bushing that rotatably supports the lower arm 6, and 26 designates a vehicle body member that supports the bushing 24. A sleeve 30, which is fixed to the first anchor arm 28 and has a spline 30a on its inner periphery, is unrotatably fitted into the spline 16b formed at the rear end of the first torsion bar 16. As is particularly clear in FIG. 3, the second torsion bar 18 is formed into a hollow shape so as to be loosely fitted into the first torsion bar 16, and has a spline 16b of the first torsion bar 16 on the inner periphery of the rear end. A non-engaging spline 18a is formed. Further, a spline 18b formed on the outer periphery of the front end of the second torsion bar 18 includes a second anchor arm 3.
A sleeve 34 having a spline 34a on the inner periphery fixed to the sleeve 2 is unrotatably fitted. In addition, in FIG. 3, the reference numeral 36 indicates the first torsion bar 16 and the sleeve 3.
A dust cover 38 is provided over the second torsion bar 18 and the sleeve 30.

As is clear from FIG. 4, the second anchor arm 32 has a sleeve 34 positioned in a recess 40a formed on the lower surface of the cross frame 40 of the vehicle body, and is further formed on the lower surface of the tip end of the second anchor arm 32. An anchor bolt 42 is provided between the recess aB32a and a recess 40b formed on the upper surface of the cross frame 40. Anchor bolt 42 is
More specifically, the contact element 44 that contacts the recess 32a,
Anchor arm 32, cross frame 40 and recess 40b
A nut 48 is screwed onto the shaft of the abutment element 46 that contacts the abutment element 46, and by tightening the nut 48, the torsional reaction force of the second torsion bar 18 and the first torsion bar 16 is increased. It is composed of

As shown in FIG. 5, the first anchor arm 28 is basically connected to the vehicle body cross frame 50 by a structure similar to that of the second anchor arm 32. A telescopic mechanism 54 is incorporated in a portion corresponding to .

The telescopic mechanism 54 has a bracket 5 attached to the cross frame 50.
6 and the cylinder 58 attached through the cylinder 5.
8; and a connecting rod 66 whose upper end is connected to the piston 60 via a pole joint 62 and whose lower end is connected to the tip of the first anchor arm 28 via a connecting pin 64. It is equipped with and a chamber 6 defined by a cylinder 58 and a piston 60.
8 is filled with oil, while the chamber 68 communicates with an accumulator 72 via a passage 70 having a control valve 69. The control valve 69 is preferably an electromagnetic on-off valve, but a type whose opening degree can be adjusted in multiple stages as necessary is used. The accumulator 72 has the same function as the well-known Akicomulator, and includes a cylinder 74 and a free piston 76 that is fitted into the cylinder 74 and partitions the inside of the cylinder into a chamber 78 and a chamber 80.
The chamber 78 is filled with oil, and the chamber 80 is filled with gas such as nitrogen gas. In FIG. 5, reference numeral 82 denotes a drain plug 8 provided at the bottom of the accumulator 72.
4 connects the passage 70 to the Akicomator 72 by means of a stopper 86.
88 is a joint that connects the passage 70 to the cylinder 58 by means of a stop 90. Note that the chamber 68 is connected via a passage 92 to a hydraulic supply/discharge device to be described later.

The suspension structure shown in FIGS. 1 to 5 above is a front suspension disposed on the right side of the vehicle body,
Although not shown, a front suspension having a similar structure is also symmetrically provided on the left side of the vehicle body.

6 and 7 show the rear suspension, and reference numeral 100 denotes left and right trailing arms 102 and 1.
The rear axle housing 106 and 106 are swingably supported by the vehicle body via 04, and lower spring supports 106 and 106 are fixed to both left and right ends of the axle housing 100, respectively. The space between each lower splash holder 106, 106 and the vehicle body is constructed as shown in FIG. That is, a bracket 108 attached to a vehicle body frame (not shown), a cylinder 110 fixed to the bracket 108, a piston 112 fitted in the cylinder 110, and an upper splash receiver 114 fixed to the piston 112. and a coil spring 116 compressed between the upper spring receiver 114 and the lower spring receiver 106. and a chamber 118 defined by cylinder 110 and piston 112.
is connected via a passage 120 to a hydraulic supply/discharge device which will be described later. Furthermore, although not shown, the trailing arm 10
2.104 Alternatively, a shock absorber is provided between the axle housing 100 and the vehicle body, and is configured so that the compressed state of the coil spring 116 is maintained even when the shock absorber is extended to its maximum amount. In FIG. 7, reference numeral 112 is a joint that connects the passage 120 to the cylinder 110 by a stopper 124, and 126 is a rubber that is fixed to the lower surface of the upper spring receiver 114 and restricts the maximum stroke of the lower spring receiver 106 relative to the upper spring receiver 114. It is a bump stopper made by.

FIG. 8 is an explanatory diagram showing the relationship between the chamber 68 in each cylinder 58 on the front side, the chamber 78 in each accumulator 72, the chamber 118 in each cylinder 110 on the rear side, and the hydraulic supply/discharge device. In FIG. 8, reference numeral 130 indicates a pump driven by an electric motor 132, and the pump 130 is of a type in which the direction of discharge is reversed depending on the direction of rotation of the motor 132. That is, when the motor 132 rotates in the direction A, it sucks oil from the port 130a and discharges the oil to the port 130b, and when the motor 132 rotates in the direction B, it sucks oil from the port 130b and discharges the oil from the port 130a. It is of the type that discharges oil. The boat 130a of the pump 130 is connected to a reservoir 136 via a check valve 134, and also connected to a reservoir 136 via a check valve 134.
It is also connected to the reservoir 136 through an orifice 138 in parallel relationship with the reservoir 136. Boat 130b is connected to reservoir 136 via check valve 140. Note that the check valves 134 and 140 are connected to the reservoir 1, respectively.
36 toward the boats 130a and 130b.

Boat 130b is also connected to chambers 68, 68 via control valves 142, 144, and check valves 146. The control valve 142 connects the boat 130a and the orifice 1.
When the pressure in the passage between the boat 130b and the control valve 144 is lower than the set pressure (for example, 3 kg/cd), it operates as a check valve that only allows oil to flow from the boat 130b toward the control valve 144.
When the pressure in the passage between the orifice 130a and the orifice 138 is higher than the set pressure, it is opened and the control valve 144 is opened to the boat 1.
It also has a function of allowing oil to flow toward 30b.

The control valve 144 has a function of being opened when the pressure in the passage between the control valve 144 and the control valve 142 is less than a set pressure (for example, 30 kg/d), and closed when the pressure is equal to or higher than the set pressure. Check valve 146 connects control valve 144 to chamber 68.
．． It has a function of only allowing oil to flow toward 68. Further, the control valve 142 is connected to a control valve 144 and a check valve 1.
It is connected to chambers 68, 68 through check valve 148 and control valve 150, which are in parallel relation to chamber 46. The check valve 148 has a function of only allowing oil to flow from the control valve 150 to the control valve 142. control valve 15
0 has a function of closing the passage between the control valve 150 and the chamber 68.68 when the pressure is less than a set pressure (for example, 14 kg/cd) and opening when the pressure is higher than the set pressure.

Furthermore, the control valve 142 has an orifice 152 and a check valve 1.
54 to the chambers 118 and 118, and the pressure in the passage between the orifice 152 and the check valve 154 is set at a set value (e.g. 50 kg/c++t).
) turns on when the value is less than ) and turns off when the value exceeds the same setting value
A high voltage switch 156 is connected. Check valve 154 has the function of only allowing oil to flow from orifice 152 toward chambers 118 and 118. The control valve 142 also has an orifice 152 and a check valve 154.
It is connected to the chambers 118, 118 through an orifice 158 and a check valve 160, which are in parallel relationship with each other, and the pressure in the passage is set at a set value ( For example, a low pressure switch 162 is connected that is turned OFF when the pressure is less than 2 kg/cd and turned ON when the pressure is equal to or higher than the set value. Furthermore, the control valve 142 has a control valve 164 that is closed when the inside of the passage between the control valve 142 and the control valve 144 is less than a set value (for example, 75 kg/cj) and is opened when it is equal to or higher than the set value. is connected to reservoir 136 via.

On the other hand, the control valve 69 is normally in an open state, but is controlled by a control circuit 165 that outputs a control signal depending on the driving state of the vehicle. That is, the control circuit 165 includes an acceleration sensor 166 (not shown) that detects longitudinal acceleration acting on the vehicle body, a steering sensor 167 (not shown) that detects the angular velocity of a steering wheel, and a vehicle height sensor 168 (not shown) that detects the vehicle height. In addition to the signal being manually generated, the output of the manual switch 169 is also manually generated. Then, when the acceleration sensor 166 detects that the longitudinal acceleration acting on the vehicle body is greater than or equal to the set acceleration, the control circuit 165 controls the control circuit 165 when the steering sensor 167 detects that the angular velocity of the steering wheel is greater than or equal to the set angular velocity. ,
Alternatively, when the vehicle height sensor 168 detects that the vehicle is in a low vehicle height state, a control signal is output to close the control valve 69 or to reduce its opening. Note that the control valve 69 is configured so that it can also be controlled by operating a manual switch 169.

FIG. 9 shows a circuit for controlling the motor 132 that drives the pump 130 shown in FIG. In FIG. 9, reference numeral 170 is a power source, and 172 is a main switch connected to the power source 170. Naoko's main switch 172
is also used as the engine key switch. Reference numeral 174 indicates a brake switch that is turned on when a brake pedal (not shown) is stepped on, and reference numeral 176 is a switch that is connected to the main switch 172 and is turned off when the brake switch 174 outputs an ON state. 178 is a vehicle speed sensor that turns on when the vehicle speed is higher than a set vehicle speed (for example, 30 ks/h). 1
80 is connected to switch 176 and contacts 182 and 184
It is a changeover switch having a movable contact 186 that selects one of the
86 contacts the contact 182, and the movable contact 186 contacts the contact 184 when the vehicle speed sensor 178 is ON. Reference numeral 188 indicates two movable contacts 190 and 192 that interlock with each other, and contact points 1 corresponding to these, respectively.
94 and 196. When the movable contact 190 is in contact with the contact 194, the movable contact 192 is not in contact with the contact 196 (when normal vehicle height is selected), and the movable contact 192 is in contact with the contact 196. When the movable contact 190 is in contact with the contact 196, the movable contact 190 is not in contact with the contact 194 (when high vehicle height is selected). Then, the on/off switch 180 is
The movable contact 192 of the select switch 188
The contact 184 is connected to the low pressure switch 162. The selection switch 188 has its movable contact 190
is connected to switch 176, its contact 194 is connected to low pressure switch 162, and its contact 196 is connected to high pressure switch 156. High pressure switch 156 and low pressure switch 162 are each connected to motor drive circuit 198. The motor drive circuit 198 is connected to the main switch 1
72 supplies power for driving the motor, and when an ON signal is input from the high voltage switch 156 side, the motor 132 is moved in the direction of arrow A in FIG.
discharges oil from its port 130b), and when an ON signal is input from the low pressure switch 162 side, the motor 132 is rotated in the direction of arrow B in FIG.
The motor 132 is rotated so that oil is discharged from the bow 130a), and the motor 132 is stopped when an ON signal is not output from either the high pressure switch 156 or the low pressure switch 162.

Next, the operation of the suspension device described above will be explained.

First, at the normal vehicle height, the front side chamber 68.
68 is set to 10kg/cd, and the rear side chamber 118.
118 is set to 2 kg/cd.

The vehicle height is now at normal vehicle height, and the main switch 172
When the selection switch 188 is operated to bring the movable contact 192 into contact with the contact 196 in order to raise the vehicle height while the switch 176 is ON, the high voltage switch 156 is ON at this time, so the motor drive circuit 198 The motor 132 of the pump 130 is rotated in the direction indicated by the arrow in FIG.

As a result, oil is discharged from the port 130b of the pump 130, and the control valves 142, 144, and check valves 14
Oil is supplied to the chambers 68 and 68 through the control valve 142 and the orifice 1, and the front vehicle height begins to rise.
Oil is also supplied to the chambers 118 and 118 via the check valve 154 and the rear vehicle height begins to rise. Then, the pressure in the passage between control valve 142 and control valve 144 is 3.
When it reaches 0 kg/cd, the control valve 144 is closed and the adjustment to raise the vehicle height on the front side is completed, and from then on, the supply of oil to chambers 68 and 68 is stopped and only oil is supplied to chambers 118 and 118. will continue. In addition, the control valve 150 has a weight of 13 kg in the passage between the control valve 150 and the check valve 14B.
/cd or more, it is opened, but since the check valve 148 is present, the chamber 68.
No oil is supplied to 68. When oil continues to be supplied to the chambers 118 and 118 and the pressure in the passage between the orifice 152 and the check valve 154 reaches 50 kg/c-, the high pressure switch 156 turns OFF and the motor drive circuit 198 starts the motor 132. By stopping the vehicle, the rear vehicle height adjustment is completed, and the vehicle height is maintained at a high vehicle height.

Next, the operation when returning the vehicle height from this high vehicle height state to the normal vehicle height will be explained.

In the high vehicle height state, when the selection switch 188 is operated to bring the movable contact 190 into contact with the contact 194 in order to return the vehicle height to the normal vehicle height, at this time the low pressure switch 162
is ON, so the motor drive circuit 198
The motor 132 of No. 0 is rotated in the direction of arrow B in FIG.

At this time, since the control valve 142 is operating as a check valve, the pump 130 pumps the check valve 1 from the reservoir 136.
Suction oil from port 130b via port 40) 13
Discharge oil from 0a. Then, the pressure in the passage between bow) 130a and orifice 138 increases to 3 kg/
When cd is reached, control valve 142 is opened and chamber 118.1
The oil in chamber 118.11 begins to drain, which causes
The pressure inside 8 also decreases and the rear vehicle height begins to decrease.

When the pressure in the passage between the control valve 142 and the check valve 148 becomes less than 30 kg/cJ, the check valve 148 opens and the oil in the chamber 68.68 also begins to drain, thereby causing the oil in the chamber 68.68 to pressure also decreases, and the vehicle height on the front side also begins to decrease. When the pressure in the chamber 68.68 further decreases and the pressure in the passage between the chamber 68.68 and the control valve 150 becomes less than 13 kg/c+f, the control valve 150 is closed and the front side vehicle height is lowered. is completed, and from now on room 6
The delivery of oil in chamber 8.68 is stopped and only the drainage of oil in chamber 118.118 continues. Then, the pressure in the passage between the control valve 142 and the Oiris 158 is 2 kg/ea.
When the pressure reaches less than f, the low pressure switch 162 is turned off, the motor drive circuit 198 stops the motor 132, and the rear vehicle height lowering adjustment is completed, thereby maintaining the vehicle height at the normal vehicle height.

In addition, the front side chamber 68.68 and the accumulator 7
2.72 means that the pressure in the same room 68.68 is 10 kg/cd
When the front suspension makes a full stroke toward the compression side, the pressure in the same chamber 68.68 is 12 kg.
/cd. Therefore, immediately after adjusting the vehicle height from the high vehicle height to the normal vehicle height as described above, the pressure inside the chamber 68.68 is 13 kg/c.
d, the front suspension then strokes toward the contraction side while driving, and the pressure in the same chamber 68.68 increases to 13.
Every time the pressure rises above kg/cd, the control valve 150 opens and oil is sent out through the check valve 148, so the pressure in the chamber 68.68 eventually settles down to about 10kg/c+d. Become. The pressure in the passage (in other words, in the chambers 118 and 118) between the check valve 148 and the iris 158 is 2 kg/c- due to the oil sent out.
In that case, the low pressure switch 16
2 is turned on, and the motor drive circuit 198 turns on the pump 130.
The pressure in the passage is increased to 2 kg/cm by rotating the motor 132 of
It can be lowered to CD.

According to the above configuration, since the pressure inside the front suspension chamber 68, 68 is maintained at a relatively low pressure (about 10 kg/cj) in the normal vehicle height state, the first and second torsion bars 16 and The effective spring constant at the front end of the first torsion bar 16, taking into consideration the pressure inside the first torsion bar 18 and the pressure inside the chambers 68 and 68, is also relatively small, and good riding comfort can be obtained. Furthermore, when driving on a road with deep ruts, by operating the selection switch 188 to the high vehicle height side (by touching the movable contact 192 to the contact 196), the pressure in the front chamber 68.68 can be increased to 30 kg/ca! Then, the pressure in the rear chamber 118, 118 is raised to 50 kg/cffI, the vehicle height is raised, and the first torsion bar 16
Since the reaction force due to the pressure in the chambers 68, 68 acting on the rear end is increased, the effective spring constant (spring constant seen from the lower arm 6) at the front end of the first torsion bar 16 also increases. As a result, even if the vehicle height is raised and the center of gravity of the vehicle becomes higher, the spring constant becomes larger, so it is possible to prevent an increase in roll or pitching of the vehicle body.

In addition, with the above configuration, even if the pressure inside the chambers 118 and 118 momentarily and suddenly exceeds 50 kg/cd due to the rear wheels passing over unevenness on the road surface while driving at a high vehicle height, the main check is performed. Due to the action of the valve 154, the orifice 158, and the orifice 152, the high pressure switch 15B is not turned on, and the pressure inside the chambers 118 and 118 is instantaneously reduced when the rear wheels pass over unevenness on the road surface while driving at the normal vehicle height. Even if the pressure suddenly exceeds 2 kg/cd, the low pressure switch 162 will not be turned on due to the action of the orifice 158, thereby inhibiting unnecessary vehicle height adjustment.

Further, as shown in FIG. 9, the brake switch 17
4 is ON, the switch 176 is turned OFF and driving of the motor 132 is prohibited.
When both the front and rear wheels are in a braking state by depressing the brake pedal (not shown), vehicle height adjustment is prohibited. This means that when at least one of the suspension arms extends in the longitudinal direction of the vehicle body, as in the above embodiment, if both the front and rear wheels are braked so that they do not move relative to the road surface, the suspension arm The arm is also locked, making it impossible to adjust the vehicle height, even if the selection switch 188
Move to the high vehicle height side to set chamber 68゜68 and chamber 118.11.
Even if the pressure inside 8 increases, the vehicle height does not rise at all, and conversely, if you take your foot off the brake pedal in this state, the vehicle height will rise rapidly, which is not only uncomfortable for the passengers, but also dangerous. It is from.

Furthermore, during sudden braking, sudden steering, or when the load on the vehicle is large, the control circuit 165 closes each control valve 69 based on the output signals of the acceleration sensor 166, steering sensor 167, or vehicle height sensor 168, respectively. Alternatively, the opening degree is controlled to be narrowed and the anchor arm 28 is locked or almost locked, so that only the first torsion bar 16 or almost only the first torsion bar 16 exerts a reaction force against the displacement of the lower arm 6. This substantially increases the spring constant of the torsion bar 14 as seen from the lower arm 16, and significantly reduces the displacement of the vehicle body during sudden braking, sudden steering, or when the vehicle is heavily loaded. can do.

Next, a modification of the present invention will be described in detail with reference to FIGS. 1O and 11. In addition, in this modified example, the parts that are substantially the same as the structure shown in the above embodiment are given the same reference numerals as those used above, and detailed description thereof will be omitted.

This modified example differs from the above embodiment in the following points:
Second torsion bar 2 in front suspension
00 is connected to the rear end of the first torsion bar 16 and extends further rearward.

For this purpose, a sleeve 202 fixed to the first anchor arm 28 and having a spline 202a on the inner periphery is unrotatably fitted onto the spline 16b formed at the rear end of the first torsion bar 16. Further, a spline 200a formed at the front end of the second torsion bar 200 is fitted into the spline 202a of the sleeve 202 so as not to rotate. Further, a sleeve 204 that is fixed to the second anchor arm 32 and has a spline 204a on the inner periphery is unrotatably fitted into a spline 200b formed at the rear end of the second torsion bar 200.

The first anchor arm 28 is also provided with a telescoping mechanism 54 similar to that shown in FIG. 5, and the telescoping mechanism 54 is controlled by a control device similar to that shown in FIGS. 8 and 9. controlled. Although not shown, a holding member is preferably provided at the rear end portion of the first torsion bar 16 or at the front end portion of the second torsion bar 200 to rotatably hold the portion relative to the vehicle body.

According to this modification, the same effects as those of the embodiment shown in FIGS. 1 to 9 can be obtained.

FIG. 12 shows a modification of the hydraulic circuit shown in FIG. 8, in which a high-pressure switch 156 is installed in one passage connecting the chamber 118, 118 and the control valve 142 to detect the pressure in the passage.
and low pressure switch 162 connect orifices 210 and 2, respectively.
12. These orifices 210
．． Reference numeral 212 is also provided to prevent unnecessary vehicle height adjustment from being started due to pressure fluctuations within the chamber 118 due to passage of unevenness on the road surface while the vehicle is running.

13 to 15 respectively show other embodiments of the front suspension in the embodiment shown in FIGS. 1 to 12 above, and these embodiments are different from those shown in FIGS.
In the embodiment shown in FIG. 2, the telescoping mechanism 54 is replaced with a telescoping mechanism having the configuration described below.

In FIG. 13, reference numeral 214 generally indicates a telescoping mechanism interposed between the vehicle body frame and the first anchor arm 28. As shown in FIG. The telescopic mechanism 214 includes a cylinder 218 whose upper end is attached to the vehicle body frame via a bracket 216;
A piston 222 is fitted into the cylinder 218 and defines a chamber 220, and its upper end is pivotally connected to the piston 222 via a ball joint 224, and its lower end is connected to the tip of the first anchor arm 28 via a connecting pin 226. A connecting rod 228 is connected to the cylinder 218, and oil is supplied to and discharged from the chamber 220 through a port 230 provided in the cylinder 218 by a supply and discharge device (not shown).

The supply/discharge device has two states: a state where the chamber 220 is communicated with a reservoir (not shown) so that the piston 222 can freely displace within the cylinder 218 (free state), and a state where oil is supplied to the chamber 220 so that the piston 222 can freely displace within the cylinder 218. It can be in a state where it is displaced to the lower end (locked state).

As a result, when the piston 222 is in a free state, the vehicle height becomes normal, and both the first torsion bar 16 and the second torsion bar 18 twist in response to suspension displacement, resulting in a soft characteristic with a relatively small spring constant. , the piston 222 is connected to the cylinder 218
When the lower end of the suspension is locked, the vehicle height increases and the first torsion bar 1 responds to the displacement of the suspension.
Only 6 is twisted and exhibits hard characteristics with a relatively large spring constant.

FIG. 14 shows another example of the telescoping mechanism. In FIG. 14, the telescopic mechanism 230 includes a cylinder 234 whose upper end is pivoted to the vehicle body frame via a stay 232, and a piston 238 fitted into the cylinder 234 and defining a chamber 236.
and a piston rod 240 whose upper end is fixed to the piston 238 and whose lower end is connected to the tip of the first sea lion arm 28 by a connecting pin 226.
The cylinder 234 is configured so that oil is supplied and discharged through a port 242 provided in the cylinder 234 by a supply and discharge device (not shown).

The supply/discharge device has two states: a state where the chamber 236 is communicated with a reservoir (not shown) so that the piston 238 can freely displace within the cylinder 234 (free state), and a state where oil is supplied to the chamber 236 so that the piston 238 can freely displace within the cylinder 234. It can be in a state in which it is displaced to the upper end (locked state).

As a result, when the piston 238 is in a free state, the vehicle height becomes normal, and both the first torsion bar 16 and the second torsion bar 18 twist in response to suspension displacement, resulting in a soft characteristic with a relatively small spring constant. , the piston 238 is connected to the cylinder 234
When the upper end of the suspension is locked, the vehicle height lowers and the first torsion bar 1 responds to the displacement of the suspension.
Only 6 is twisted and exhibits hard characteristics with a relatively large spring constant.

FIG. 15 shows yet another example of the telescoping mechanism. In FIG. 15, the telescopic mechanism 244 includes a cylinder 246 whose lower end is connected to the distal end of the first anchor arm 28 by a connecting pin 226, and an upper chamber 248 and a lower chamber fitted into the cylinder 246. 250, and a piston rod 254 whose lower end is fixed to the piston 252 and whose upper end is pivoted to the vehicle body frame. It is configured such that oil is supplied and discharged via ports 256 and 258 by a supply and discharge device (not shown).

The supply/discharge device allows both the upper chamber 248 and the lower chamber 250 to communicate with the reservoir so that the piston 252 can freely displace within the cylinder 246 (free state), and supplies oil to the upper chamber 248. A state in which the lower chamber 250 is communicated with the reservoir and the piston 252 is displaced to the lower end of the cylinder 246 (10th closed state);
50, the upper chamber 248 is communicated with the reservoir, and the piston 252 is displaced to the upper end of the cylinder 246 (20th closed state).

As a result, when the piston 252 is in a free state, the vehicle height becomes normal, and both the first torsion bar 16 and the second torsion bar 18 twist in response to suspension displacement, resulting in a soft characteristic with a relatively small spring constant. , the piston 252 is connected to the cylinder 246
When the lower end of the suspension is locked (10th locked state), the vehicle height increases and the first
Only the torsion bar 16 is twisted, exhibiting a hard characteristic with a relatively large spring constant, and furthermore, the piston 252 is locked to the upper end of the cylinder 246! ! J (second
When the vehicle height is lowered and the suspension is displaced, the first torsion bar 16
Only the spring is twisted and exhibits a hard characteristic with a relatively large spring constant.

In this way, vehicle height adjustment and spring constant control can be performed even in the suspension device equipped with the telescoping mechanism shown in FIGS. 13 to 15 above, but depending on the purpose of the vehicle or how it is used. Selected appropriately. For example, if the vehicle is mainly used for normal city driving and high-speed driving,
It is preferable to have a vehicle that can be switched between a state where the vehicle height is normal and the spring constant is small, and a state where the vehicle height is low and the spring constant is large. It is preferable to have a vehicle that can be switched between a low spring constant state and a high vehicle height state with a high spring constant. It is preferable to be able to switch between a state where the height is normal and the spring constant is small, a state where the vehicle height is low and the spring constant is large, and a state where the vehicle height is high and the spring constant is large.

〔Effect of the invention〕

As described above, according to the present invention, vehicle height adjustment and spring constant control can be performed at the same time by appropriately controlling the telescoping mechanism. Not only can we provide a torsion bar type suspension ml that can handle rough road driving or high speed driving that requires a low center of gravity, but we can also control the control valve regardless of whether the vehicle height is adjusted. As a result, the spring constant of the torsion bar can be controlled, so it is also possible to cope with so-called attitude control that reduces changes in attitude depending on the driving state of the vehicle.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a front suspension according to an embodiment of the present invention, FIG. 2 is an enlarged plan view of part 2 in FIG. 2, and FIG. 3 is a sectional view taken along the line 4 is a sectional view taken along line IV-IV in FIG. 3, FIG. 5 is an enlarged sectional view of the expansion mechanism 54 and accumulator 72 in FIG. 1, and FIG. 6 shows the rear suspension according to the above embodiment. Perspective view,
FIG. 7 is an enlarged sectional view showing the coil spring 116 portion of FIG. 6, FIG. 8 is an explanatory diagram showing the hydraulic supply/discharge device according to the above embodiment, and FIG. 9 is a control circuit according to the above embodiment. 10 is a perspective view showing a modification of the present invention, FIG. 11 is a sectional view taken along the line XI-XI of FIG.
The figure is an explanatory diagram showing a modification of the hydraulic supply/discharge device shown in Fig. 8, Fig. 13 is a sectional view showing another telescopic mechanism that can be adopted in the front suspension, and Fig. 14 is another example of the telescopic mechanism. FIG. 15 is a sectional view showing still another example of the expansion and contraction mechanism. 6... Lower arm, 16... First torsion bar,
118... Second torsion bar, 28... First anchor arm, 32... Second anchor arm, 54... Telescopic mechanism, 69... Control valve, 72... Accumulator applicant Mitsubishi Motors Corporation Co., Ltd.

Claims (1)

[Claims] In a suspension equipped with a torsion bar, one end of which is unrotatably supported by a suspension arm and the other end of which is unrotatably supported by the vehicle body, an arm is unrotatably provided in the middle of the torsion bar, and the same a hydraulic expansion and contraction mechanism interposed between the arm and the vehicle body; an accumulator that communicates with a hydraulic chamber of the expansion and contraction mechanism; and a liquid supply and discharge device that controls supply and discharge of liquid in the hydraulic pressure chamber; A torsion bar suspension device characterized by comprising a control valve that controls mutual communication between the hydraulic chamber and the accumulator.